The knowledge gap hypothesis suggests that educated individuals or groups of individuals acquire technology driven information at a faster rate (and more overall information) than that attained by less educated individuals (Tichenor, Donohue et al. 1970). The net effect of the knowledge gap is that the disparity between advantaged and disadvantaged groups will increase. The knowledge gap hypothesis is not specific for health related issues, and in addition, does not specify that the actual information gained by more privileged individuals is accurate or beneficial.

This hypothesis has relevance to public health. For example, it is possible that health disparities between wealth and poor individuals are at least partially attributable to differences in acquisition of technology driven information. On an individual level, Beacom and Newman described specific information behaviors, from “active information seeking” to “information of avoidance” (Beacom and Newman, 2010). These various information behaviors are meaningful when considering the knowledge gap hypothesis. For example, if all people in a population are identical in information seeking behaviors, but only those with higher socioeconomic status have access to such sources of information as the Internet, then these advantaged individuals will have a greater chance of acquiring health information.

An abundance of health information is available in television news and talk shows, and in newspapers and magazines. When the knowledge gap hypothesis was first presented in 1970, these sources of health information may not have been universally available, but probably are now, at least in the United States. In contrast, the Internet, a rich source of health information, is not currently available to everyone. The Internet, providing information on any possible illness, symptom, or health-related issue imaginable, has been shown to be considerably lower in availability among low-income households than in high-income households (U.S. Census Bureau, 2009). Also, lower income individuals also have fewer basic computer skills than individuals in higher socioeconomic classes (Schmeida and McNeal, 2007). Lastly, the ability to appropriately comprehend health information found on the Internet is important. General and health illiteracy is exceeds 20% in the United States (National Insitute for Literacy, 2010, Schmeida and McNeal, 2007; Beacom and Newman). Therefore, assuming that health information on the Internet is accurate, then individuals who are socioeconomically advantaged will be more likely to have access to the Internet, more likely to possess computer skills, and be more likely to fully understand the health information presented on websites. All of these factors potentially contribute to better health of the economically advantaged through constructs of the knowledge gap hypothesis.

However, a critical question needs to be addressed: “Is technology-driven health information accurate?” It has been suggested that television, being widely available in the United States and in many other countries, may reduce gaps in knowledge between well-educated and poorly educated individuals (Kwak, 1999). For a reduction in a knowledge gap to genuinely occur, the knowledge provided by a medium must be factual and accurate. There appears to be a difference in the accuracy and completeness of content in health-related television and television news and newspaper coverage compared to that found on the Internet. For television and newspaper coverage of cancer-related stories including etiology, survival, and other aspects, Niederdeppe et al., examined content for accuracy and completeness (Niederdeppe et al, 2010). Local television stories about cancer tended to focus on cancer causes, proven or otherwise, including numerous controversial causes such as cell phone use and unproven various dietary/nutritional parameters. Newspaper articles were somewhat better: television news stories were less likely than newspaper articles to provide information regarding additional resources about the issue in question, making validation somewhat difficult by an individual. In addition, local television reports about cancer may promote fatalistic beliefs that “everything causes cancer”, or that “there are too many recommendations about cancer” (Niederdeppe and Levy, 2007).

Similar studies performed to determine the accuracy of cancer-related (and other, non-cancer-related) health information provided on the Internet seem to indicate a somewhat better situation in terms of accurate and complete content (Shim 2008; Eysenbach 2003). Interestingly, people who utilize the Internet for cancer-related information are better-informed patients according to a study by Lee et al. (Lee, Gray et al.). With this improvement in content of Internet-based health information comes the need for 1) Internet access, 2) basic computer skills, and 3) an ability to comprehend more sophisticated information that is generally provided in newspaper or television reports related to health, since Internet content may be written at “college level” understandability (Friedman, Hoffman-Goetz et al. 2006).

In spite of the great potential to inform, even a cursory look provides evidence that the Internet is an opportunity for people with access and computer skills to be misinformed. The content of some health-related websites is essentially opinions represented at times as factual information. Here's a recent newsprint article from England that illustrates this point, and has relevance to the health of young women (http://topnews.co.uk/215701-hpv-vaccine-failure-blamed-misinformation-online).

It is imperative that efforts to improve literacy also pay attention to health literacy, as it is clear that the internet represents a powerful but at times misleading tool for promotion of public health measures. It is likely that for many people, the Internet will be an increasingly important source of health-related information. Clinicians need to be sure that patients have access to accurate information, and must be sure to inform in language that everyone can understand.

References:
Friedman, D. B., L. Hoffman-Goetz, et al. (2006). "Health literacy and the World Wide Web: comparing the readability of leading incident cancers on the Internet." Med Inform Internet Med 31(1): 67-87.
Kwak, N. (1999). “Revisiting the knowledge gap hypothesis: education, motivation, and media use” Communication Research 26 (4): 385-413.
Lee, C. J., S. W. Gray, et al. (2010). "Internet use leads cancer patients to be active health care consumers." Patient Educ Couns. National Insitute for Literacy (http://lincs.ed.gov/)
Niederdeppe, J., E. F. Fowler, et al. (2010). "Does Local Television News Coverage Cultivate Fatalistic Beliefs about Cancer Prevention?" J Commun 60(2): 230-253.
Niederdeppe, J. and A. G. Levy (2007). "Fatalistic beliefs about cancer prevention and three prevention behaviors." Cancer Epidemiol Biomarkers Prev 16(5): 998-1003.
Schmeida, M. and R. S. McNeal (2007). "The telehealth divide: disparities in searching public health information online." J Health Care Poor Underserved 18(3): 637-47.
Shim, M. (2008). "Connecting internet use with gaps in cancer knowledge." Health Commun 23(5): 448-61.
Tichenor, P. J., G. A. Donohue, et al. (1970). "Mass media flow and differential growth in knowledge." Public Opinion Quarterly 34(2): 159-170.
US Census Bureau, http://www.census.gov/population/www/socdemo/computer/2009.html